Alkene metathesis with directly fluorinated alkenes is challenging, limiting its application in the burgeoning field of fluoro‐organic chemistry. A new nickel tris(phosphite) fluoro(trifluoromethyl)carbene complex ([P₃Ni]=CFCF₃) reacts with CF₂=CF₂ (TFE) or CF₂=CH₂ (VDF) to yield both metallacyclobutane and perfluorocarbene metathesis products, [P₃Ni]=CF₂ and CR₂=CFCF₃ (R=F, H). The reaction of [P₃Ni]=CFCF₃ with trifluoroethylene also yields metathesis products, [P₃Ni]=CF₂ and cis/trans‐CFCF₃=CFH. However, unlike reactions with TFE and VDF, this reaction forms metallacyclopropanes and fluoronickel alkenyl species, resulting presumably from instability of the expected metallacyclobutanes. DFT calculations and experimental evidence established that the observed metallacyclobutanes are not intermediates in the formation of the observed metathesis products, thus highlighting a novel variant of the Chauvin mechanism enabled by the disparate four‐coordinate transition states.

中文翻译：

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含氟烯烃的镍氟碳烯复分解

直接氟化烯烃进行烯烃复分解具有挑战性，限制了其在新兴的氟有机化学领域中的应用。一种新的三（亚磷酸酯）氟（三氟甲基）碳镍配合物（[P ₃ Ni] = CFCF ₃）与CF ₂ = CF ₂（TFE）或CF ₂ = CH ₂（VDF）反应生成金属环丁烷和全氟碳烯复分解产物，[P ₃ Ni] ＝ CF ₂，CR ₂＝ CFCF ₃（R ＝ F，H）。[P ₃ Ni] = CFCF ₃与三氟乙烯的反应也产生复分解产物，[P ₃ Ni] = CF ₂和顺/反-CFCF ₃ = CFH。但是，不同于与TFE和VDF的反应，该反应形成金属环丙烷和氟镍烯基物质，这可能是由于预期的金属环丁烷的不稳定性所致。DFT计算和实验证据表明，所观察到的金属环丁烷不是所观察到的复分解产物形成的中间产物，从而突显了Chauvin机制的新变体，该变体由不同的四坐标过渡态实现。